The optical film composite disclosed herein can be used as a device for achieving the brightness enhancing and light diffusing functions, especially in a liquid crystal display (LCD) device. In general, an LCD displays a desired image on its screen by controlling the transmittance of light from a backlight unit using a plurality of liquid crystal cells arranged in a matrix and a plurality of control switches for converting video signals which will be provided to each of the liquid crystal cells.
The backlight unit is classified as either an edge type or a direct type depending on the placement of its light source with respect to the liquid crystal panel. In the edge type, a light guide plate (which converts linear light of the lamp to planar light) is necessary because the lamp is placed on the side. But in the direct type, the light guide plate is not necessary because the lamp is placed under the surface of the liquid crystal panel. Direct type backlights are more widely used for large-sized LCD devices such as TVs due to higher optical efficiency, simpler structure and lack of size limitation for the display surface.